Lymphatic territories (lymphosomes) in a canine: an animal model for investigation of postoperative lymphatic alterations.

Suami H, Yamashita S, Soto-Miranda MA, Chang DW - PLoS ONE (2013)

Bottom Line:
Lymphatic patterns in the carcass were then compared with postoperative lymphatic patterns in the live dogs.Our canine lymphosome map allowed us to observe lymphatic collateral formations after lymph node dissection in live dogs.This canine model may help clarify our understanding of postoperative lymphatic changes in humans in future studies.

Affiliation: The Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America. hsuami@mdanderson.org

ABSTRACT

Background: Lymph node dissection is often performed as a part of surgical treatment for breast cancer and malignant melanoma to prevent malignant cells from traveling via the lymphatic system. Currently little is known about postoperative lymphatic drainage pattern alterations. This knowledge may be useful for management of recurrent cancer and prevention of breast cancer related lymphedema. We mapped the complete superficial lymphatic system of a dog and used this canine model to perform preliminary studies of lymphatic architectural changes in postoperative condition.

Methods: Lymphatic territories (lymphosomes) were mapped with 4 female mongrel carcasses using an indocyanine green (ICG) fluorescent lymphography and a radiographic microinjection technique. Two live dogs were then subjected to unilateral lymph node dissection of lymph basins of the forelimb, and ICG lymphography and lymphangiogram were performed 6 months after the surgery to investigate lymphatic changes. Lymphatic patterns in the carcass were then compared with postoperative lymphatic patterns in the live dogs.

Results: Ten lymphosomes were identified, corresponding with ten lymphatic basins. Postoperative fluorescent lymphographic images and lymphangiograms in the live dogs revealed small caliber lymphatic network fulfilling gaps in the surgical area and collateral lymphatic vessels arising from the network connecting to lymph nodes in the contralateral and ipsilateral neck in one dog and the ipsilateral subclavicular vein in another dog.

Conclusion: Our canine lymphosome map allowed us to observe lymphatic collateral formations after lymph node dissection in live dogs. This canine model may help clarify our understanding of postoperative lymphatic changes in humans in future studies.

pone-0069222-g005: Montage of indocyanine green (ICG) lymphographic images of the left forelimb of the live dog prior to lymph node dissection.The ventral superficial lymph node (arrow) was identified using injections of ICG at interdigital webspaces.

Mentions:
After the dog was anesthetized with isoflurane, ICG fluorescent lymphography was used to demonstrate normal lymphatic pathways and accurately identify the locations of the lymph nodes prior to surgery (Fig 5). The ICG injection sites were either in interdigital webspaces in the forefoot – for locating the ventral cervical node – or on the medial side around the elbow joint, for locating the axillary lymph node. A skin incision of 10 cm was made above each lymph node. Isosulfan blue (Lymphozurin; Covidien, Mansfield, MA) was injected into the same sites as those used for ICG to stain the lymphatic vessels. Skin flaps were undermined with a very superficial layer because some lymphatic vessels ran immediately beneath the skin. Subcutaneous fat tissue, including the lymphatic vessels, was excised together with the underlying deep fascia and lymph node. Stamps of both the afferent and efferent lymphatic vessels were ligated or clipped. The skin incisions were closed with dermal and skin stitches, and penrose drains were inserted into the wound. Circumferential measurements of the operated forelimb at the paw, wrist, middle of the forearm, and elbow were recorded every other day for 3 weeks.

pone-0069222-g005: Montage of indocyanine green (ICG) lymphographic images of the left forelimb of the live dog prior to lymph node dissection.The ventral superficial lymph node (arrow) was identified using injections of ICG at interdigital webspaces.

Mentions:
After the dog was anesthetized with isoflurane, ICG fluorescent lymphography was used to demonstrate normal lymphatic pathways and accurately identify the locations of the lymph nodes prior to surgery (Fig 5). The ICG injection sites were either in interdigital webspaces in the forefoot – for locating the ventral cervical node – or on the medial side around the elbow joint, for locating the axillary lymph node. A skin incision of 10 cm was made above each lymph node. Isosulfan blue (Lymphozurin; Covidien, Mansfield, MA) was injected into the same sites as those used for ICG to stain the lymphatic vessels. Skin flaps were undermined with a very superficial layer because some lymphatic vessels ran immediately beneath the skin. Subcutaneous fat tissue, including the lymphatic vessels, was excised together with the underlying deep fascia and lymph node. Stamps of both the afferent and efferent lymphatic vessels were ligated or clipped. The skin incisions were closed with dermal and skin stitches, and penrose drains were inserted into the wound. Circumferential measurements of the operated forelimb at the paw, wrist, middle of the forearm, and elbow were recorded every other day for 3 weeks.

Bottom Line:
Lymphatic patterns in the carcass were then compared with postoperative lymphatic patterns in the live dogs.Our canine lymphosome map allowed us to observe lymphatic collateral formations after lymph node dissection in live dogs.This canine model may help clarify our understanding of postoperative lymphatic changes in humans in future studies.

Affiliation:
The Department of Plastic Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America. hsuami@mdanderson.org

ABSTRACT

Background: Lymph node dissection is often performed as a part of surgical treatment for breast cancer and malignant melanoma to prevent malignant cells from traveling via the lymphatic system. Currently little is known about postoperative lymphatic drainage pattern alterations. This knowledge may be useful for management of recurrent cancer and prevention of breast cancer related lymphedema. We mapped the complete superficial lymphatic system of a dog and used this canine model to perform preliminary studies of lymphatic architectural changes in postoperative condition.

Methods: Lymphatic territories (lymphosomes) were mapped with 4 female mongrel carcasses using an indocyanine green (ICG) fluorescent lymphography and a radiographic microinjection technique. Two live dogs were then subjected to unilateral lymph node dissection of lymph basins of the forelimb, and ICG lymphography and lymphangiogram were performed 6 months after the surgery to investigate lymphatic changes. Lymphatic patterns in the carcass were then compared with postoperative lymphatic patterns in the live dogs.

Results: Ten lymphosomes were identified, corresponding with ten lymphatic basins. Postoperative fluorescent lymphographic images and lymphangiograms in the live dogs revealed small caliber lymphatic network fulfilling gaps in the surgical area and collateral lymphatic vessels arising from the network connecting to lymph nodes in the contralateral and ipsilateral neck in one dog and the ipsilateral subclavicular vein in another dog.

Conclusion: Our canine lymphosome map allowed us to observe lymphatic collateral formations after lymph node dissection in live dogs. This canine model may help clarify our understanding of postoperative lymphatic changes in humans in future studies.